Ground-State Modulation Using Optical Double Resonance in Trivalent Rare-Earth-Doped Single Crystals

Abstract

We report a double-resonance technique that can substantially increase our knowledge of the many complex and competitive processes operative in materials such as the trivalent rare-earth-doped single crystals. This technique, which modulates the ground-state population, is similar in many respects to the Bloembergen quantum counter and the Varsanyi infrared-optical double-resonance experiment. The similarity and differences of the three techniques are analyzed and discussed. Ground-state modulation has been observed in single crystals of CaW${\mathrm{O}}_4$: 2% ${\mathrm{Tm}}^{3+}$ and Cd${\mathrm{F}}_2$: 5% ${\mathrm{Ho}}^{3+}$. The applications of this technique to determine the dominant process of competing mechanisms are discussed. This technique may also be used to resolve ambiguities present in optical spectra of the trivalent rare-earth-doped single crystals and as a possible negative ↔ positive image converter.